IFC 4.3.2.20240809 (IFC4X3_ADD2) under development

6.2.3.9 IfcDistributionSystem

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6.2.3.9.1 Semantic definition

A distribution system is a network designed to receive, store, maintain, distribute, or control the flow of a distribution media. A common example is a heating hot water system that consists of a pump, a tank, and an interconnected piping system for distributing hot water to terminals.

The group IfcDistributionSystem defines the occurrence of a specialized system for use within the context of building services or utilities for built facilities.

Important functionalities for the description of a distribution system are derived from existing IFC entities:

6.2.3.9.2 Entity inheritance

6.2.3.9.3 Attributes

# Attribute Type Description
IfcRoot (4)
1 GlobalId IfcGloballyUniqueId

Assignment of a globally unique identifier within the entire software world.

2 OwnerHistory OPTIONAL IfcOwnerHistory

Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object,

3 Name OPTIONAL IfcLabel

Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.

4 Description OPTIONAL IfcText

Optional description, provided for exchanging informative comments.

IfcObjectDefinition (7)
HasAssignments SET [0:?] OF IfcRelAssigns FOR RelatedObjects

Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.

Nests SET [0:1] OF IfcRelNests FOR RelatedObjects

References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical structures only).

IsNestedBy SET [0:?] OF IfcRelNests FOR RelatingObject

References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).

HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions

References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.

IsDecomposedBy SET [0:?] OF IfcRelAggregates FOR RelatingObject

References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definition can be aggregated by several other objects (occurrences or parts).

Decomposes SET [0:1] OF IfcRelAggregates FOR RelatedObjects

References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definition can only be part of a single decomposition (to allow hierarchical structures only).

HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects

Reference to the relationship objects, that associates external references or other resource definitions to the object. Examples are the association to library, documentation or classification.

IfcObject (5)
5 ObjectType OPTIONAL IfcLabel

The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED or when the concrete entity instantiated does not have a PredefinedType attribute. The latter is the case in some exceptional leaf classes and when instantiating IfcBuiltElement directly.

IsDeclaredBy SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects

Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.

Declares SET [0:?] OF IfcRelDefinesByObject FOR RelatingObject

Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.

IsTypedBy SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects

Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.

IsDefinedBy SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjects

Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.

IfcGroup (2)
IsGroupedBy SET [0:?] OF IfcRelAssignsToGroup FOR RelatingGroup

Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object.

ReferencedInStructures SET [0:?] OF IfcRelReferencedInSpatialStructure FOR RelatedElements

Reference to the relationship IfcRelReferencedInSpatialStructure that relates the group to a spatial element.

IfcSystem (2)
ServicesBuildings SET [0:1] OF IfcRelServicesBuildings FOR RelatingSystem

Reference to the spatial structure via the objectified relationship IfcRelServicesBuildings, which is serviced by the system.

ServicesFacilities SET [0:?] OF IfcRelReferencedInSpatialStructure FOR RelatedElements

Reference to the relationship IfcRelReferencedInSpatialStructure that relates the system to a spatial element.

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IfcDistributionSystem (2)
6 LongName OPTIONAL IfcLabel

Long name for a distribution system, used for informal purposes. It should be used, if available, in conjunction with the inherited Name attribute.

7 PredefinedType OPTIONAL IfcDistributionSystemEnum

A list of types to further identify the object. Some property sets may be specifically applicable to one of these types.

Table 6.2.3.9.B

6.2.3.9.4 Formal propositions

Name Description
CorrectPredefinedType

Either the PredefinedType attribute is unset, or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.

NOT(EXISTS(PredefinedType)) OR
 (PredefinedType <> IfcDistributionSystemEnum.USERDEFINED) OR
 ((PredefinedType = IfcDistributionSystemEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType))
Table 6.2.3.9.C

6.2.3.9.5 Property sets

  • Pset_Condition
    • AssessmentDate
    • AssessmentCondition
    • AssessmentDescription
    • AssessmentType
    • AssessmentMethod
    • LastAssessmentReport
    • NextAssessmentDate
    • AssessmentFrequency
  • Pset_DistributionSystemCommon
    • Reference
  • Pset_DistributionSystemTypeElectrical ELECTRICAL
    • ElectricalSystemType
    • ElectricalSystemCategory
    • Diversity
    • NumberOfLiveConductors
    • MaximumAllowedVoltageDrop
    • NetImpedance
    • RatedVoltageRange
  • Pset_DistributionSystemTypeOverheadContactlineSystem OVERHEAD_CONTACTLINE_SYSTEM
    • SpanNominalLength
    • ContactWireStagger
    • ContactWireNominalDrop
    • PressureRange
    • ContactWireNominalHeight
    • ContactWireUplift
    • ElectricalClearance
    • NumberOfOverlappingSpans
    • PantographType
    • TensionLength
    • OCSType
  • Pset_DistributionSystemTypeVentilation VENTILATION
    • DesignName
    • DuctSizingMethod
    • PressureClass
    • LeakageClass
    • FrictionLoss
    • ScrapFactor
    • DuctSealant
    • MaximumVelocity
    • AspectRatio
    • MinimumHeight
    • MinimumWidth
  • Pset_InstallationOccurrence
    • InstallationDate
    • AcceptanceDate
    • PutIntoOperationDate
  • Pset_MaintenanceStrategy
    • AssetCriticality
    • AssetFrailty
    • AssetPriority
    • MonitoringType
    • AccidentResponse
  • Pset_MaintenanceTriggerCondition
    • ConditionTargetPerformance
    • ConditionMaintenanceLevel
    • ConditionReplacementLevel
    • ConditionDisposalLevel
  • Pset_MaintenanceTriggerDuration
    • DurationTargetPerformance
    • DurationMaintenanceLevel
    • DurationReplacementLevel
    • DurationDisposalLevel
  • Pset_MaintenanceTriggerPerformance
    • TargetPerformance
    • PerformanceMaintenanceLevel
    • ReplacementLevel
    • DisposalLevel
  • Pset_PowerControlSystem ELECTRICAL
    • AssemblyInstruction
  • Pset_ProcessCapacity
    • ProcessItem
    • ProcessCapacity
    • ProcessPerformance
    • DownstreamConnections
    • UpstreamConnections
  • Pset_RepairOccurrence
    • RepairContent
    • RepairDate
    • MeanTimeToRepair
  • Pset_Risk
    • RiskName
    • RiskType
    • NatureOfRisk
    • RiskAssessmentMethodology
    • UnmitigatedRiskLikelihood
    • UnmitigatedRiskConsequence
    • UnmitigatedRiskSignificance
    • MitigationPlanned
    • MitigatedRiskLikelihood
    • MitigatedRiskConsequence
    • MitigatedRiskSignificance
    • MitigationProposed
    • AssociatedProduct
    • AssociatedActivity
    • AssociatedLocation
  • Pset_ServiceLifeFactors
    • QualityOfComponents
    • DesignLevel
    • WorkExecutionLevel
    • IndoorEnvironment
    • OutdoorEnvironment
    • InUseConditions
    • MaintenanceLevel
  • Pset_TractionPowerSystem ELECTRICAL
    • PowerSupplyMode
    • ElectrificationType
    • RatedFrequency
    • NominalVoltage

6.2.3.9.6 Concept usage

Concept Usage Description
IfcRoot (2)
Revision Control General

Ownership, history, and merge state is captured using IfcOwnerHistory.

Software Identity General

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

IfcObjectDefinition (9)
Classification Association General

Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system.

Aggregation General

No description available.

Approval Association General

No description available.

Constraint Association General

No description available.

Document Association General

No description available.

Library Association General

No description available.

Material Association General

No description available.

Material Single General

No description available.

Nesting General

No description available.

IfcObject (5)
Object Predefined Type General

No description available.

Object Typing General

Any object occurrence can be typed by being assigned to a common object type utilizing this concept. A particular rule, restricting the applicable subtypes of IfcTypeObject that can be assigned, is introduced by overriding this concept at the level of subtypes of IfcObject.

This concept can be applied to the following resources:

Object User Identity General

An attribute Name and optionally Description can be used for all subypes of IfcObject. For those subtypes, that have an object type definition, such as IfcBeam - IfcBeamType, the common Name and optionally Description is associated with the object type.

Property Sets with Override General

Any object occurrence can hold property sets, either directly at the object occurrence as element specific property sets, or at the object type, as type property sets. In this case, the properties that are provided to the object occurrence are the combinations of element specific and type properties. In case that the same property (within the same property set) is defined both in occurrence and type properties, the property value of the occurrence property overrides the property value of the type property.

Assignment to Group General

No description available.

IfcGroup (2)
Group Assignment General

The IfcGroup establishes an arbitrary collection of objects through utilizing this concept.

Property Sets for Objects General

This concept can be applied to the following resources:

IfcSystem (2)
Property Sets for Objects General

This concept can be applied to the following resources:

System Element Attributes General

No description available.

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IfcDistributionSystem (2)
Group Assignment General

For the most common case of an IfcDistributionElement subtype containing ports of a particular PredefinedType that all belong to the same distribution system, the IfcDistributionElement is assigned to the IfcDistributionSystem via the IfcRelAssignsToGroup relationship, where IfcDistributionPort's are implied as part of the corresponding system based on their PredefinedType. An IfcDistributionElement may belong to multiple systems, however only one IfcDistributionSystem of a particular PredefinedType.

For rare cases where an IfcDistributionElement subtype contains ports of the same PredefinedType yet different ports belong to different systems, alternatively each IfcDistributionPort may be directly assigned to a single IfcDistributionSystem via the IfcRelAssignsToGroup relationship, where the PredefinedType must match. Such assignment indicates that the IfcDistributionSystem assigned from the IfcDistributionPort overrides any such system of the same PredefinedType assigned from the containing IfcDistributionElement, if any.

Additionally, an IfcDistributionSystem may in turn be assigned to an IfcDistributionPort indicating the host or origination of the system using IfcRelAssignsToProduct.

Figure 6.2.3.9.A — Distribution system assignment

Instance diagram for electrical circuit
Figure 6.2.3.9.A — Distribution system assignment
Property Sets for Objects General

This concept can be applied to the following resources:

Table 6.2.3.9.D

6.2.3.9.7 Formal representation

ENTITY IfcDistributionSystem
 SUPERTYPE OF (ONEOF
	(IfcDistributionCircuit))
 SUBTYPE OF (IfcSystem);
	LongName : OPTIONAL IfcLabel;
	PredefinedType : OPTIONAL IfcDistributionSystemEnum;
 WHERE
	CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR
 (PredefinedType <> IfcDistributionSystemEnum.USERDEFINED) OR
 ((PredefinedType = IfcDistributionSystemEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
END_ENTITY;

6.2.3.9.8 References

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6.2.3.9.9 Changelog

6.2.3.9.9.1 IFC4

  • New resource

6.2.3.9.9.2 IFC4.3_DEV_20bdb3d

  • where rule, CorrectPredefinedType